Block Attachment with free Webmail sites

Dear All
I have in my network ISA server 2004 & Websense server, what I need to know. Is there any way to allow users access to free webmail servers (like hotmail.com or yahoo.com) and in the same time prevent them to send any attachments using those servers? So they can only send Email without any attachments?
Thanks in advance for your sincere cooperation.

i can't block certain URL for delivering mail attachments, as there are a lot of free webmail servers. but if there are any addons for ISA 2004 that make this process, it will be a great help to inform me about it

You can certainly do it - either with add-ons or without. Doing it without is harder though.

Right-click your outbound http rule and select configure http
In here you will see the options for signatures, headers and the like.

YOU will need to identify the headers and signatures you want to block though.
Assumning you have ISA2004 sp3 installed, using the monitoring-logging section of the ISA gui you can drill down and see the http headers and user-agents that are used when posts are made for attachements etc.
Because the configure http option is set for that specirfic rule onl;y (not globally) you can define and refine your rules to allow what you want at a good level of granularity - but it takes time and effort to get it right.

Some of the add-ons from Websense, GFI Web Monitor etc can also do this - most of these have a 30 day eval that you can downlaod and install and test with.

so we are back to the first solution, which will require to know all the URLs of attaching pages, and there are noway to know all webmail servers attaching pages URLs.
concerning websense there are a solution but for IM attaching, but not for webmail attaching.

Featured Post

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Password hashing is better than message digests or encryption, and you should be using it instead of message digests or encryption. Find out why and how in this article, which supplements the original article on PHP Client Registration, Login, Logo…

Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, Just open a new email message. In the To field, type your recipient's fax number @efaxsend.com.
You can even send a secure international fax — just include t…